nixVersions.nix_2_20: init at 2.20.5

Changelog: https://github.com/NixOS/nix/blob/2.20.5/doc/manual/src/release-notes/rl-2.20.md

pkgs/tools/package-management/nix/common.nix

@@ -15,6 +15,7 @@ let
   atLeast210 = lib.versionAtLeast version "2.10pre";
   atLeast213 = lib.versionAtLeast version "2.13pre";
   atLeast214 = lib.versionAtLeast version "2.14pre";
+  atLeast220 = lib.versionAtLeast version "2.20pre";
   atLeast221 = lib.versionAtLeast version "2.21pre";
   # Major.minor versions unaffected by CVE-2024-27297
   unaffectedByFodSandboxEscape = [
@@ -48,6 +49,7 @@ in
 , lib
 , libarchive
 , libcpuid
+, libgit2
 , libsodium
 , libxml2
 , libxslt
@@ -126,6 +128,8 @@ self = stdenv.mkDerivation {
     gtest
     libarchive
     lowdown
+  ] ++ lib.optionals atLeast220 [
+    libgit2
   ] ++ lib.optionals stdenv.isDarwin [
     Security
   ] ++ lib.optionals (stdenv.isx86_64) [

pkgs/tools/package-management/nix/default.nix

@@ -258,6 +258,11 @@ in lib.makeExtensible (self: ({
     ];
   };
 
+  nix_2_20 = common {
+    version = "2.20.5";
+    hash = "sha256-bfFe38BkoQws7om4gBtBWoNTLkt9piMXdLLoHYl+vBQ=";
+  };
+
   # The minimum Nix version supported by Nixpkgs
   # Note that some functionality *might* have been backported into this Nix version,
   # making this package an inaccurate representation of what features are available